Water at the bottom (inside) of my refrigerator. Why? How?

I have a Maytag Dual Cool (model MTB 2155 AR). No idea how old. It
came with the house. Been working fine until a couple weeks ago.

The freezer is on top.

I open the door and look down and I can see that, under the veggie /
fruit crispers there is water. It's spilling out from under the
drawers. I take the two drawers out and under them, in a slightly
indented section all along the bottom of the fridge obviously designed
to catch spills, there is water.

This may be normal except the drain hole is plugged up. Look for some drain
in the bottom of the refrigerator. It usually goes down this hole to a
catch pan at the bottom of the refrigerator and then evaporates.

The drain hole may even be at the bottom/rear of the freezer
compartment.
If so, it connects to a tube that goes down the back of the
refrigerator to the drip pan in the bottom.

The hole or tube is probably clogged. When it's clogged, water runs
down the inside of the refrigerator during each defrost cycle.
I've had luck with simply a long length of stranded wire that I've
used to ream out/clean out the hole and drain tube.

THE WEIRD THING IS: the sides and back of the fridge down there are
dry. That's what I can't figure out: where is this water coming from?
If it was dripping down from above, wouldn't the sides or back also be
wet? If this were outside, I'd say the water was welling UP from the
ground. But, no, I don't see any holes in the spill catch area. It
takes about 24 hours to replenish.

Has it been especially humid where you live? And, does the unit have a hi-lo
humidity switch?